Tim Wong may work as an aquatic biologist during the day, but when he is back on terra firma he tends to other wildlife: raising endangered butterflies in his backyard.

Studying butterflies had been a childhood hobby of Wong’s, so creating a backyard conservation area wasn’t a life-changing metamorphosis for him—but it certainly was for this species, which had vanished from the San Francisco skyline.

When he first learned of the predicament of the pipevine swallowtail, the 28-year-old swooped in to help by creating a screened backyard enclosure with ideal environmental conditions for the insect.

He filled it with specific plants that the insects like to feed on. Then, he gathered a group of 20 different pipevine swallowtail caterpillars from nearby areas. As he carefully nursed the small tribe of precious insects, their numbers began to quickly multiply.